Sensor probes may be used for measuring parameters such as environmental conditions. The sensor probe may be inserted into an object or fixed in close proximity thereto and can monitor the environmental conditions of the object or to which it is exposed. The sensor probe may be permanently positioned or alternatively they may be temporarily positioned and used only to measure the environmental conditions of the object periodically. Temperature may be one of the most commonly measured parameters by sensor probes. Several types of sensors may be used for measuring temperature, such as thermocouples, thermistors and resistance temperature detectors (RTDs).
Whilst thermocouples, thermistors and RTDs have been used for many years to monitor temperatures, and may well continue to play an important role in industry, there may be emerging applications that require a sensor probe with a suite of sensors and the thermocouples, thermistors and RTDs cannot easily conform. For example, thermocouples, thermistors and RTDs are typically used for measuring temperature and provide a voltage as their output, making them impractical in certain situations.
One particular use of sensor probes is the monitoring of objects being transported. For example sensor probes may be placed in packaging along with the object to be transported. In this manner, environmental conditions to which the object is exposed during transportation may be detected by the probe. This may indicate to entities responsible for the transportation of the object whether or not the object has been exposed to environmental conditions which may be detrimental to the integrity of the object. This is typically done by associating each sensor probe with a monitoring unit which can record measurements provided by the sensor probe and communicate such measurements to the responsible entities via a display screen of the monitoring unit, or a data communication link, or the like.
As objects can be in transportation for prolonged periods of time, sensor probes which consume small amounts of power may be desirable so that battery life of the probe or monitoring unit, where applicable, may be improved. Furthermore, providing a sensor probe and monitoring unit with each object may not be conducive to scalability and may also result in unnecessary cost.
There is accordingly a need for a sensor probe which addresses at least some of the problems identified above.